Gas fired appliances, for example gas fireplaces, include exhaust vents, which are often coupled with fresh air intakes. Exhaust and intake ducts or pipes may be routed from the appliance upward, through a chimney or a chase, to terminate on an exterior of a building, which houses the appliance. At this termination, the exhaust and intake pipes may extend, or be extended, side-by-side or coaxially into a chimney cap. These caps, which surround the external openings of exhaust and intake pipes, are typically designed to separate the exhaust from the fresh air intake, to control air flow, and to be aesthetically pleasing.